I thought I'd throw out a little history on my name.
There is a blog I would comment on from time to time and when leaving a comment I had to choose from a pull down menu. I guess I didn't realize at the time which to use so I chose "anonymous". I would then sign of with "j" at the end of every post so the blogger would know it was me. By the time I figured out how to comment using a profile from other sites on the menu I didn't feel like starting over as a stranger so I just kept on doing what I was doing.
When it came time to pick a name for this site, AnonymousJ just popped in my head first. The question mark block that comes standard as an avatar seemed to be perfect as it was so I went with it.
Not much of a story, but there is more history to it than simply being secretive and lazy :)
it's funny what leads to our names. My name on 1up was "Sneenlantern" because when I made it up I was majorly into DC heroes and I just put Snee + Green lantern. It's still my name on Xbox and PS3 and stuff, I guess I feel it's kind of clever. 
At the time I sat down to create a name, I was reading transmetropolitan and in love with Metro 2033. So, I created a portmanteau of sorts.
My username comes from my childhood dog's name. I used it as my log-on back in the early days of the internet (for either a Sierra fan site or a specifically King's Quest fan site) and have been using it for internet stuff ever since. The number just came from randomly adding on numbers until I got a username that hadn't been used before.
While I could claim I got my name from The Watchmen that would be a lie. I started using the name after reading the Mothman Chronicles and spending time on line looking up the lore of this mythical beast. I'm also uncoordinated so if you've ever watched a moth fly around bumping into light sources well that's kinda like me trying to play the original RE games, walking in circles and bumpng into things.
Interesing story. When I created this name almost a year ago now, I figured I was pretty much the youngest person on the site. Only after making it did I realize that eventually I won't be a "kid" anymore ( I'm 14 so I'm not really sure if that constitutes as a kid or not) but I think even when I'm older I'll keep this name. The name has sort of grown on me.